Risk factors and visual outcome of Non-Arteritic Ischemic Optic Neuropathy (NAION): Experience of a tertiary center in Kuwait

Abstract

Background: Non-arteritic ischemic optic neuropathy (NAION) is the most common acute optic neuropathy over the age of 50 years. NAION is commonly associated with systemic vascular risk factors (diabetes, hypertension, hyperlipidemia) and small cup-to-disc-ratio. We have assessed the prevalence risk factors of NAION and the visual outcome in patients referred to a tertiary ophthalmology center in Kuwait.

Materials and methods: A retrospective review of new cases of NAION presenting within 2 weeks of onset were included and baseline clinical and demographics characteristic were determined. The prevalence of risk factors and the visual outcome (change in logMAR visual acuity, mean deviation of visual field) was compared between young NAION patients (below 50 years of age) and older NAION patients (over 50 years of age). The odds ratio of a final favorable visual outcome (visual acuity 20/40 or better) by age category was determined.

Results: Seventy-eight eyes of 78 patients with recent onset NAION were included in the study. The most prevalent risk factors for NAION in our subjects were diabetes (64.1%), small cup-to-disc ratio (61.5%), hyperlipidemia (51.3%) and hypertension (38.5%). Young NAION patients had better final logMAR visual acuity (0.55 +- 0.57) then older NAION patients (0.9 +- 0.73), (p = 0.03). Furthermore, young NAION patients were 2.8 times more likely to have a final visual acuity of 20/40 or better than older NAION patients, odds ratio (OR), 2.87; 95% confidence interval (CI), 1.12-7.40, Chi-square p-value = 0.03).

Conclusion: There is a high prevalence of systemic vascular risk factors and small cup-to-disc ratio in NAION patients referred to our center across different age groups (below and above 50 years). Patients below the age of 50 years with NAION are more likely to have a final visual acuity of 20/40 or better than NAION patients above the age of 50 years.

Fig 1

Box plot showing the comparison between baseline (A) and final (B) logMAR visual acuity between young (below 50) and older NAION (over 50). The horizontal line in the box plot represents the mean. NS = not statistically significant (p > 0.05). SS = statistically significant (p ≤0.05).